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An Duong 09/04/2017 at 07:31
We have \(\dfrac{SP}{PB}=\dfrac{area\left(APS\right)}{area\left(ABP\right)}=\dfrac{5}{6}\)
Call the area of PSR be x, the area of CSR be y, we have:
\(\dfrac{area\left(PSR\right)}{area\left(PBR\right)}=\dfrac{SP}{PB}=\dfrac{5}{6}\)
\(\Rightarrow\dfrac{x}{7}=\dfrac{5}{6}\) \(\Rightarrow x=\dfrac{35}{6}\)
\(\dfrac{BR}{CR}=\dfrac{area\left(BSR\right)}{area\left(CRS\right)}=\dfrac{7+x}{y}\) (1)
\(\dfrac{BR}{CR}=\dfrac{area\left(ABR\right)}{area\left(ACR\right)}=\dfrac{13}{x+y+5}\) (2)
(1), (2) => \(\dfrac{7+x}{y}=\dfrac{13}{x+y+5}\)
\(\Rightarrow y=\dfrac{\left(7+x\right)\left(5+x\right)}{6-x}=\dfrac{5005}{6}\)
So, \(area\left(ABC\right)=5+6+7+x+y\)
\(=5+6+7+\dfrac{35}{6}+\dfrac{5005}{6}=858\)
John selected this answer. -
FA KAKALOTS 28/01/2018 at 22:09
A B C R S P 5 6 7 M N x y
We have SPPB=area(APS)area(ABP)=56
Call the area of PSR be x, the area of CSR be y, we have:
area(PSR)area(PBR)=SPPB=56
⇒x7=56
⇒x=356
BRCR=area(BSR)area(CRS)=7+xy
(1)
BRCR=area(ABR)area(ACR)=13x+y+5
(2)
(1), (2) => 7+xy=13x+y+5
⇒y=(7+x)(5+x)6−x=50056
So, area(ABC)=5+6+7+x+y
=5+6+7+356+50056=858